The temperature of a certain substance can be seen as the average speed of the atoms or molecules in that substance. In the liquid state of a substance the forces between the atoms or molecules are strong enough to keep them together, however with enough freedom to move, unlike in the solid state. If we would have a closer look at the surface of a liquid from sideways, we would see water molecules jumping out of the water and reentering it again. The lower the water temperature would be the lesser the amount of water molecules leaving the liquid phase would be. If water would be heated up and the temperature will reach 100 degrees C at normal atmospheric pressure, more water molecules would leave the water than reentering. Boiling has started. The temperature of the water remains at 100 degrees C, if the heating continues as the average speed of molecules will not increase, only the rate of molecules leaving the water will increase, until all the water in liquid state has been vapourized. The amount of heat needed to vapourize liquid water is called latent heat. Latent heat is a very important driving factor in the atmosphere and thus the weather.
Consider the acid spill. It is already starting to do nasty things to, say, the floor or counter. So you grab the bottle of 10% NaOH and pour some on the spill. All of a sudden, you get a great deal of heat, and you don't have any visual evidence whether your put on too little or too much. But you have added more liquid to the spill, generated more heat, and will get more damage. You have made a bigger mess, and if you added too much, you then have a neutralization problem to deal with.
And if it is something like a strong sulfuric acid solution, adding sodium hydroxide solution will be extremely exothermic, and you could get some really nasty results.
So now approach the spill with a handful of baking soda. You sprinkle it on the spill. It fizzes, and carbon dioxide is given off. That actually, in a very tiny way, moderates the temperature of the neutralization. And you can keep adding baking soda until the fizzing stops, and then perhaps some water to mix everything well. But what you have done is kept the volume to a minimum, added a neutralization agent that has a visible endpoint (no more gas being given off), and you don't suddenly have a huge amount of highly basic solution because you added too much.
And what is also nice about baking soda is that you can toss some with your hand or even with a spoon, and get some distance from the spill. With a liquid, you have to get much closer
i hope this helped..
Answer: option D.
The total number of atoms of each element on both sides of the
equation must be the same.
Explanation:
Answer:
Correct answers: 2 and 3
Explanation:
1- correct would be: Isolation of ibuprofen is not dangerous, but it is necessary because only one enantiomer has effect on interaction with biologic <em>diana</em>
<em>2: Correct! This property of diastereomeric salts (differing solubilities) is really useful for the isolation of the original enantiomers</em>
<em>3: Correct! we can only observe their properties, like polirized light rotation or separation in an assimetric column for chromatography.</em>
4: correct would be: diastereomeric salts do not rotate light, they have lost the property of anantiomers that originated them
